There is an ever increasing demand for power conversion and regulation circuitry to operate with increased efficiency and reduced power to accommodate the continuous reduction in size of electronic devices. Switching regulators have been implemented as an efficient mechanism for providing a regulated output in power supplies. One such of regulator is known as a switching regulator or switching power supply, which controls the flow of power to a load by controlling the on and off duty-cycle of one or more switches coupled to the load. Many different classes of switching regulators exist today.
Switching regulators can be implemented in any of a variety of applications. One such application is in a control system for disk-drive spindle motors. It is sometimes desirable to be able to monitor a magnitude of current that flows through the switches of a switching regulator for a disk-drive spindle motor, such as to control a rotational speed of the disk-drive spindle motor. Some spindle motor power regulator integrated circuits (ICs) may incorporate additional input/output (I/O) pins to accommodate an external sense resistor and/or associated sensing circuitry. Such methods thus can be subject to additional cost and/or space to incorporate the additional I/O pins and the associated circuitry. In addition, typical current sensing schemes for spindle motor power regulators may incorporate a sense resistor that interconnects all of the low-side power transistors with ground or a common low voltage rail, such that the current that is sensed is an aggregate current of each of the phases of the spindle motor.